As Horus was slain and the Emperor mortally wounded at the end of the Horus Heresy, Abaddon tore the Lightning Claw (the "Talon of Horus") from Horus's armour and retreated with the Traitor Legions to the Eye of Terror. Abaddon renamed the Sons of Horus as the Black Legion to expunge the name of Horus, who failed in his attempt to take over the Imperium. He carries the Daemon Sword Drach'nyen, which flays the souls from those it strikes. No other leader has been able to command the loyalty of all the nine Traitor Legions.

Since then he has led several raids and invasions against the Imperium of Man. He has waged 13 full-scale Black Crusades from the Eye of Terror; in the most recent assault, Abaddon managed to gain a foothold in the Cadian Gate, although he was unable to consolidate his gains and they have largely been snatched from his grasp by a vicious counterattack from the Imperial Navy. Thus far his ultimate victory has always been prevented.